大跨曲线钢桁梁人行桥竖向、横向和扭转振型耦合强,人致振动舒适度评价和减振控制难度大。以湖南省长沙市浏阳河一主跨为120 m的曲线双层桥面三跨连续钢桁梁桥—汉桥为工程背景,通过理论分析和人群激励现场动力试验,识别桥梁固有模态参数,评价人致振动舒适性,优化设计调谐质量阻尼器(Tuned Mass Damper,TMD)并评价TMD的减振效果。研究表明:因桥梁第一阶竖弯模态和第一阶扭转模态的阻尼比仅为0.23%和0.3%,人致振动加速度不满足舒适性要求;采用竖向TMD进行竖弯模态和扭转模态的减振控制,减振后的桥梁满足舒适性要求。
“土木工程新材料”是针对大土木学科背景研究生开设的一门专业学位课,首先分析了该课程特点以及传统教学方法弊端;以研究生为中心、学习成果为导向,对教学内容与模式、互动方法和考核方式进行了重构,提出了师生讲授各半、随机双向互动、课题报告答辩的新型教学方法。设计了调查问卷进行效果评价,结果表明绝大部分研究生高度认可师生讲授各半的教学内容与模式、随机与双向提问的互动方法、PPT答辩与课程报告的考核方式,喜欢具有幽默、互动、温和特点的授课教师;课程效果整体评价优秀率86%、优良率达100%。通过两年的教学实践,该教学方法可作为其他土木类研究生课程教学改革的重要参考。“New Materials for Civil Engineering” is a professional degree course for graduate students with a background in major civil engineering disciplines. First, the characteristics of the course and the shortcomings of traditional teaching methods are analyzed. Based on graduate-centered and learning outcome-oriented ideas, the teaching content, mode, interaction method and assessment method have been reconstructed, and a new teaching method has been proposed with teachers and students giving half lectures, random two-way interaction, and project report reply. A questionnaire was designed to evaluate the effect, and the results showed that the vast majority of postgraduate students highly recognized the teaching content and mode of half-teaching by teachers and students, the interactive method of random and two-way questioning, and the assessment method of PPT defense and course report. They liked humorous, interactive teachers with gentle characteristics;the overall evaluation rate of course effectiveness is 86%, and the excellent rate is 100%. Through two years of teaching practice, this teaching method can be used as an important reference for the teaching reform of other civil engineering postgraduate courses.
